1. Field of the Invention
This present invention is directed to: top drives used in wellbore operations which include, but are not limited to, drilling operations and tripping operations; pipe handlers; and service loop assemblies. In certain particular aspects, the present invention is directed to new top drive systems in which, within a derrick, a tubular rotating apparatus is selectively separable from a tubular hoisting apparatus permitting the hoisting apparatus to be used in tubular operations below the rotating apparatus while the tubular rotating apparatus is secured above the tubular hoisting apparatus within the derrick.
2. Description of Related Art
There are a wide variety of known drilling rigs, top drive systems and methods of their use, examples of which are in the exemplary U.S. patents and applications: U.S. Pat. Nos. 7,931,077; 7,882,902; 7,628,229; 7,513,312; 7,472,762; 7,320,374; 7,231,969; 7,228,913; 7,222,683; 7,188,686 6,923,254; 6,705,405; 6,679,333; 6,609,565; 6,536,520; 6,276,450; 6,007,105; 5,921,329; 5,503,234; 5,501,286; 5,433,279; 5,381,867; 5,251,709; 5,038,871; 4,984,641; 4,878,546; 4,872,577; 4,813,493; 4,807,890; 4,800,968; 4,767,100; 4,753,300; 4,458,768; 4,421,179; 4,437,524; 4,005,851; 3,835,940; 3,483,933; and U.S. application Ser. No. 11/823,854 filed Jun. 28, 2007—all of which are incorporated fully herein for all purposes.
It is well known to use a top drive drilling unit to rotate the drill stem of an oil and gas well; see, for example, U.S. Pat. Nos. 4,449,596; 3,464,507; and 3,766,991 and U.S. application Ser. No. 050,537, filed Apr. 20, 1993. In many cases, a top drive drilling unit is suspended by a cable from the crown of a mast of a drilling rig above a drill string. The unit rotates the drill string from the top side as opposed to the use of a rotary table and related equipment at the rig floor. A top drive unit often has a track which runs the length of the mast to guide the top drive, to restrain it from lateral movement and to transfer reactive torque and torsional loads originating from the drilling operation into the derrick substructure. Typical torque drive track systems are disclosed in U.S. Pat. Nos. 4,865,135 5,251,709 and in U.S. patent application Ser. No. 217,689, filed Mar. 24, 1994. In the process of drilling a well, it may be advantageous to disconnect the drill string from the top drive unit and handle sections of drill pipe without the top drive unit in place. In these instances, the top drive unit is disconnected from the draw works and moved away from immediately above the drill string. See, for example, U.S. Pat. Nos. 4,421,179; 4,437,524 and 4,458,768.
U.S. Pat. No. 4,437,524 discloses a well drilling apparatus designed to eliminate the need for a rotary table, kelly and kelly bushing, and includes a drilling unit which is shiftable between a drilling position in vertical alignment with a mousehole, and an inactive position.
U.S. Pat. No. 4,449,596 discloses a top drive well drilling system that includes pipe handling equipment that facilitates the making and breaking of connections to the drill string during the drilling cycle.
U.S. Pat. No. 4,458,768 discloses a top drive well drilling system having a drilling unit shiftable to various positions, wherein the shifting movement is accomplished by means of a structure that guides the unit for movement along predetermined paths.
U.S. Pat. No. 4,605,077 discloses a top drive drilling system having a motor which is connected to the upper end of the drill string and moves upwardly and downwardly therewith.
U.S. Pat. No. 4,625,796 discloses an apparatus comprising a stabbing guide and a back-up tool, wherein the apparatus can function in aligning an additional length of pipe with the upper end of the drill string and thereby facilitates the controlled stabbing of pipe length for addition into the top of a drill string. U.S. Pat. No. 4,667,752 discloses a top head drive well drilling apparatus with a wrench assembly and a stabbing guide, wherein the wrench assembly is mounted on the drive unit and the stabbing guide is mounted on the wrench assembly.
U.S. Pat. No. 5,501,286 discloses and apparatus and method for displacing the lower end of a top drive torque track suspended from a derrick wherein a drive unit is disconnected from the drill string and suspended from the torque track. The top drive suspended from the torque track can then be moved away so as not to interfere with the addition or removal of drill string sections. U.S. Pat. No. 5,755,296 discloses a portable top drive comprising a self-contained assembly of components necessary to quickly install and remove a torque guide and attendant top drive unit in a drilling rig mast.
Conventional service loops hold and house a variety of hoses, conduits, and cables that, among other things transfer electrical, hydraulic and compressed-air power to a top drive. Such service loops are mounted in a drilling derrick and travel up and down under a control of a piece of traveling equipment There are various combinations of hoses, wires and cables that pass through the inside diameters of the service loops. Some top drives utilize a combination of two to four service loops which can have approximately equal length. Each service loop at one end is attached to the derrick (or mast), and at the opposite end is connected to the top drive. As the top drive travels up and down, the service loops move accordingly up and down. In addition, they have a bending movement in the transverse direction, which forms the respective bend radii.
Service loops can vary from about 2 inches to 7 inches in diameter. Variation in paths during operation of the machinery can cause the loops to become entangled. When this happens, loops with the larger diameter can force loops with the smaller diameter into unnatural positions, and this can result in premature failure of the loops with the smaller diameter.
Also, an environmental condition such as a strong wind can be a factor that accelerates failure of the loops. Also, in some cases two or more loops with the smaller diameter can displace a loop with the larger diameter, which can cause problems including broken loops.